The charity’s new Bred for Looks – Born to Suffer campaign highlights the plight of pint-sized pooches condemned to a life of disease and disability by “cosmetic breeding” – and the owners who are left with eye-watering bills.

Last year, 400 people who could not cope with these tiny dogs’ problems ended up dumping them – 44 per cent up on the year before.

The RSPCA has found many owners are conned by the word “pedigree” into thinking a pup is fit and well, instead of following simple, sensible precautions like those in the panel (right).

Zoe Whitehead, a 20-year-old hairdresser from Hull, was left devastated when her teacup chihuahua pup Bella died.

Suffering: Bella died a day after Zoe bought her

Bella was born the size of a teacup and weighed just 270g (9.5oz) when she collapsed at nine and a half weeks old – two days after Zoe paid £400 for her from an online “pedigree” seller.

Zoe said: “Bella was a bit wobbly when I got her. I thought she was just tired.”

But when Bella refused food and water, Zoe rushed her to the vet where she died the next day. The pedigree papers Zoe was given turned out to be fake.

Zoe said: “I had become so attached to Bella in that short time. Seeing her suffer was terrible. I’m just glad she got the chance to spend time with someone who loved her before she died.”

Paula Codling had to have her West Highland white terrier, Buster, put down when he developed health problems.

Paula, 38, from Essex, said: “I bought Buster after seeing an advert on the internet but when we brought him home his behaviour was bizarre and he had diarrhoea. He was put on antibiotics but he never recovered. He had one eye bigger than the other, which I was told could be due to in-breeding.”

Buster was playing in the back garden when he suffered a massive seizure and the vet advised Paula, who had already shelled out £1,000 in health bills, to have him put down.

Paula said: “The seller told me he was eight weeks old, but he turned out to have been just six weeks. What happened was very upsetting and I’m still angry.”

The RSPCA’s Claire Calder added: “A cute puppy is hard to resist but not looking beyond that can result in thousands of pounds in vets’ bills and a pedigree pet with long-lasting health and welfare problems.”

Zoe heeded advice before buying her next pup, Lola, a pedigree schnoodle.

Happy: Zoe's new pup Lola

She said: “Lola’s completely healthy and her breeder is always checking on her. But I still think of Bella. I won’t forget her.”